December 28, 2010

There are growing discussions about which type of alcohol makes the best solvent for spirit varnish, shellac and subsequently French polish. The leading favorite seems to be straight grain alcohol or ethanol over denatured alcohol which is mostly wood alcohol [methanol]. This may only be relevant to the United States as other countries sell denatured alcohol which is ethanol with unpalatable instead of poisonous denaturing agents added. So that stuff will just make you puke instead of making you go blind and dying.

Everclear™ is a commercially available straight grain alcohol if you purchase the 190 proof. They do sell a 150 proof alcohol which will not work for thinning shellac, French polish or spirit varnish, as it contains too much water. So check the label carefully. It is not available in some states.

Here are some definitions:

Absolute alcohol [anhydrous alcohol] – is pure alcohol with less than 1% water and is 200 proof. Laboratory grade and not for human consumption [traces of benzene] but makes a great solvent.

Alcohol – C2H5H or C2H6O made from the distillation of grain, starch or sugar, is colorless, volatile, flammable liquid has an agreeable odor and burnt taste. Ethanol has a specific gravity of 0.789 – 0.81, a molecular weight of 46.0414, with a dielectric constant of 24.3 to 33 at 68° (F), is a solvent for many gums, resins, etc., lamp fuel that has a flash point of 55.4° F and boils at 172° F. Isopropyl alcohol contains water and should not be used as a solvent. Over time alcohol which has an affinity for water will absorb it and become useless. Alcohol is best stored in a tightly stoppered glass container.

Azeotrope – is a mixture of alcohol and water which cannot be separated by simple distillation resulting in a 190 proof [95% alcohol, 5% water].

Denatured alcohol – is ethanol alcohol made poisonous by the addition of methanol [wood alcohol], acetone, benzene and other nasty ingredients to keep people from drinking the stuff. You cannot remove the hazardous components by distillation, filtering through bread or stratification. In other countries the alcohol is made unpalatable rather than poisonous.

Ethanol – C2H6O is alcohol made from grains and is the safe form of alcohol with a specific gravity of 0.789 and a molecular weight of 46.0414. Ethanol has a flash point of 55.4° F and boils at 172° F. Ethanol is more viscous and less volatile than methanol.

Methyl alcohol – CH3OH [methanol, 1932] wood alcohol, is made from the distillation of wood {originally boxwood} and is extremely poisonous and used as a denaturing agent for ethanol. It has a specific gravity of 0.7913, a molecular weight of 32.04, a flash point of 54° F and a boiling point of 148.4° F. A sip of this stuff will make you go permanently blind and a shot [1 ounce] is fatal. Methanol is less viscous and more volatile than ethanol.

Proof – is the ratio of alcohol to water. Originally determined by putting alcohol on gunpowder, if it is at least 100 proof (50% alcohol), when ignited will ignite the gunpowder.

I for one like the fact that the pure straight grain alcohol is not going to kill me, unless I drink too much of it, nor make me ill by breathing the stuff. I tried using denatured alcohol in my alcohol torch [lamp] with a coil of platinum wire wrapped around the wick, which becomes incandescent when ignited. Worked great, very hot and when I accidently breathed in the fumes, I dropped to my knees. Nasty, nasty fumes. I switched over to pure grain alcohol and no nasties.

As for the difference as a solvent for spirit varnish, for the same reason, it smells good. As for a shellac thinner works about the same as near as I can tell, but does smell better. When it comes to French polish many people swear by pure grain alcohol, describing its ease of use and other descriptive terms like ‘buttery’ and ‘creamy’, etc., are applied. I like the stuff for French polish as well it seems to be smoother during application.

I am afraid I cannot tell after all has dried, which is which. The results appear to be the same, just a difference in ease of application. I am avoiding all of the problems by making my own grain alcohol, see here.

December 23, 2010

After a couple of days weather delay, the Amtrak train is running again and I will catch it this evening. I had the option of riding one of their buses but I have done that before and would rather be keel-hauled.

Upon arrival in Reno, I will be picked up at the depot and then a couple hours more on the highway over Donner Pass [may stop for lunch] then on to Sacramento area to visit family, then back the same day to Reno.

After that I want to hold very still.

Looking forward to the trip, visiting family and enjoying some time off.

Well, I finally got it all together. Here is a photograph of the shaped ‘Dutchman’ after the hide glue had dried. Delicate endgrain always make these a challenge. I also used liquid shellac to ‘fill’ in the very small chips around the bobbin. It took between 30 to 40 ‘coats’, little daubs of shellac put in the chips and allowed to dry. I smoothed them down in between and added more. I could have used hot stick shellac, but I wanted to try this, all in all it took about an hour total to get the edge of the bobbin smooth with the shellac fill.

Here is a closeup of the Farnham Accelerator head with its braided corn husk bearings, the string is hemp that I first got wet, stretched and allowed to dry. Two simple opposing overhand knots tie the two ends together. The large power string is also hemp treated in the same manner.

This is the tensioning devise in place and with a coat of stain. I used linseed oil/turpentine with dry powdered pigments, yellow ocher for the first coat, then burnt umber with a bit of black iron oxide for the next coat. All sealed with a coat of thin shellac. I used thin shellac so as not to give too much shine, which would not match the originals.

The compleated wheel, ready for the customer to pick up.

And here is the happy customer spinning some raw wool she brought along to field test the wheel in my shop. She was impressed with the accelerator head.

Great project, just got an inquiry from a lady in Hawaii to repair her great-grandmother’s spinning wheel.

December 15, 2010

I had to make a threaded tensioning devise for the wool wheel. Because I don’t have a tap and die set to cut this particular external thread, I had to cut it by hand. But I first needed to determine the number of threads per inch and the pitch of the threads. I measured the diameter required being 7/8″, then rolled up a small piece of paper and put it into the hole. With my finger I was able to force the paper into the threads, leaving an impression on the paper.

I took the paper out, darkened the lines and added new ones parallel to the ones on the pattern. I then rubbed some graphite on the back of the paper, wrapped it around the 7/8″ maple turned dowel I happen to have, a handle for another tool that had a split so I didn’t use it for that task. I had to position the threads to leave the end protruding to press against the hinged upright that I have fabricated.

I transferred the pattern to the wood then using a fine back saw [the only one I have] I cut the valleys of the threads. After the spiral kerf was cut, I then marked the peaks of the threads in the center between adjoining kerfs. I add this after the cuts, so as not to get confused as to what is a peak and what is a valley. Turned out to be 3 threads per inch.

Then with a sharp chisel, I formed the threads. After the initial forming I tested to see if it worked and it worked First Time. Now I need to decide how long the handle should be, not too long as it will interfere with the wheel, and what style to make it; round, octagonal or flattened off like a thumb screw?

December 13, 2010

The wool walking spinning wheel that I am working on got a new distaff and an unusual one indeed. I have seen dozens and dozens of distaffs, from symmetrical tree saplings to fancy turned examples. This one is unusual in that the curved parts are rattan and there are only three pieces. The lower holes are drilled through and are offset from one another. Each end of the three pieces are tapered to fit into the upper holes.

After I shaped the ends with a small bronze spokeshave, I glued them in place, followed later with a coat of shellac that made them match the one original still remaining.

I also worked on the accelerator head and fashioned two ‘turned’ ends that hold the large wheel, they are of birch. I sawed the shoulders, split off the waste and fashioned the tenons with a float. I then used a gimblet bit to drill holes in each to accept the axle of the large wheel. I will stain them later.

I also had to repair a chip in the mandrel pulley. Like all it is end grain and is very small. I have probably done several hundred of these small repairs.

After sawing the side pieces, I used a flexible metal ruler to scribe a line, then took a knife and pared down the waste wood to the line.

I then cut an eight inch piece of birch, then used my knife to cut the angle, it was actually a split as it was end grain. Once one angle was established, I put the new piece in place and used the knife to mark the proper length. I then used some fish glue to glue it in place.

After it dries tomorrow I will carefully shape it and give it a stain then some shellac.

December 9, 2010

I have had this wheel for a while, so it is time to get it finished. It was missing its upright and spindle. The owner wanted an accelerator head for this wheel and after searching around the Internet she found one that I will be able to put in good working order. She also has a distaff that needs a bit of work.

This is how it came into the shop. The shop location has changed and so has the wheel. What was missing is the upright and in the above picture it would be to the left of the small tensioning upright.

I started with a rough piece of white oak from Mike Moore [Mick Moore’s Custom Mill], it was a 3 inch square piece that came from some long skids, the stuff was very dry and very hard. I took the edges of with my Ft. Meigs ax to make it acceptable on the lathe.

After it came off the lathe. It is much too long, it will need to be cut down to bring the accelerator’s head down to the proper position.

This is what the upright looks like in position with a temporary threaded tension device, but first I had to saw in the hinge. A saddle, bridle or open mortise and tenon, this hinge joint has many names.

I sawed off the base just over two inches above the bead, then marked the tenon for the saddle/hinge joint. Some tough rip sawing.

I have since drilled a 3/8″ hole through, secured with a maple peg and rounded the ends of the hinge mechanism. It only moves an arc of about 15 degrees, just enough to put tension on and take tension off the power string.

December 2, 2010

A quick repair for some friends. They travel around the country and take this with them on their adventures. It has suffered from the extremely dry climate here in the west and has dried out and the top was cracked in two places and the two joints were open and or loose.

The table is 35 1/2″ in diameter, the top is just under 1/2″ in thickness and made of cedar. It is 10 1/4 tall and has folding legs so it can be easily set aside when not in use, also handy for transportation. It took some time to remove the top, which had been nailed onto the apron. I used a long blade putty knife and a wooden mallet and wedges to convince the top it couldn’t stay attached to the apron.

You can see in the photograph the two breaks in the top.

I took the loose, bad joints apart and had to plane the edges in order to make the joint tight. Because it is an oriental table I pulled the plane instead of pushing. Interesting bamboo dowels, they are pointed at both ends. Once the joints were good, I toothed them with a toothing plane.

I repaired the cracks in the center section first, leaving off each side, so I could put some pressure to bring the cracks together. I allowed it to dry overnight then washed off the excess glue. Because they are vegetarians I used fish glue as they don’t eat terrestrials.

I then glued the two end sections on to the center section this morning the mallet and jar of resin is for weight to hold down the table flat, counteracting the pressure of the clamp and clamp extender. Tomorrow I will adjust the edges at the joints, peg it onto the apron and put a coat of hemp seed oil to protect.

December 1, 2010

There is always one last little thing to get a job done and a small tapered peg to hold the axle of the wheel into the upright. It required fitting to hold but not restrict the rotating axle, so it is tapered in length. I did this from a split of maple then used a float to smooth it out. Be careful the float can easily skin a knuckle.

I stained it dark with shellac and burnt umber pigment, put it in place and the wheel was compleat.

Back in working order, the customer was very happy.

Now on to the Wool Walking Wheel, have to make a hinged post and fit up the accelerator head, should be fun.